ECORP on the Leading Edge of eDNA Identification Methodology

What is eDNA?
Environmental DNA (eDNA) is nuclear or mitochondrial DNA that is released from an organism into the environment. Sources of eDNA include shed skin, mucous, gametes, feces, hair, and carcasses. The DNA of a range of aquatic organisms can be detected in water samples at very low concentrations using qPCR (quantitative Polymerase Chain Reaction), conventional PCR, and/or DNA sequencing technology.
In California, ECORP staff have been involved in an effort for the Central Valley Clean Water Association (CVCWA) and a consortium of 47 wastewater treatment facilities to evaluate the efficacy of using eDNA for determining the presence or absence of California native freshwater mussels in Central Valley water bodies. In addition, ECORP staff have assisted on eDNA projects with listed large branchiopods, trout species, mountain yellow-legged frog, and chytrid fungus.
How can an eDNA survey benefit my project?
The use of eDNA can significantly reduce the necessity for traditional surveying methods, typically reducing costs while improving detection. With eDNA methodology, the visual identification or handling of target species would not be required to confirm their presence or absence. The eDNA methodology can be used to:
  • Determine presence/absence of listed species in a given project area (e.g., Chinook salmon, steelhead, large branchiopods, California red-legged frog, California tiger salamander)
  • Guide preliminary presence/absence assessments or additional survey efforts
  • Facilitate early detection of recolonizing invasive species after their intentional removal from mitigation/restoration sites
  • Determine, during a preliminary site assessment, whether invasive species (e.g., northern pike and other invasive fish, zebra and quagga mussels, bullfrog, and chytrid fungus) exist that may lessen the chance of special-status species occurring Quickly assess the spread of newly introduced invasive species
  • Evaluate the success and spread of native species being reintroduced or simply being tracked for other purposes
  • Map presence/absence of species to assist with larger scale projects (e.g., restoration plans, agency projects, County projects, State projects)
  • Demonstrate occupied habitat at mitigation sites
  • Assess temporal (e.g., before/after a construction project) and spatial (e.g., upstream vs. downstream of a point source discharge) impacts
  • Confirm regulatory compliance (e.g., freshwater mussel presence or absence for ammonia compliance)
How long does environmental DNA persist in water?
In aquatic environments, eDNA persists for a relatively short amount of time (3-4 weeks maximum) because it degrades with exposure to environmental conditions (e.g., light, oxygen, pH, salinity, substrates, and the microbial community). Due to this short persistence duration, eDNA detections can be confidently interpreted as proof of target species presence.
Where can you use the method?
In California, eDNA methods have been tested in a variety of habitats, and have been used to detect a range of organisms, including mussels and other aquatic invertebrates, fish, amphibians, branchiopods, mammals, and water birds.
How can I learn more about eDNA services from ECORP?
ECORP has been developing its eDNA service through partnerships with local research organizations at the University of California, Davis, and William Jessup University, among others. ECORP can help you understand how eDNA technology can help your organization, whether you are planning a project in an area with sensitive resources or are an agency in need of water supply analysis.
For more information, contact David Thomas or Jason Peters in the Rocklin office at (916) 782-9100; or Todd Chapman or Brian Zitt in the Santa Ana office at (714) 648-0630.

About ECORP Consulting, Inc.

ECORP Consulting, Inc. has assisted public and private land owners with environmental regulation compliance since 1987. Find out more at ECORP Consulting's mission is to consistently deliver high-quality environmental consulting services through outstanding science and timely, creative solutions for our clients, while providing an excellent work environment for our staff.
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